LM7805 is a commonly used three-terminal regulator, generally used in TO-220 package, can provide DC 5V output voltage, a wide range of applications, including overcurrent and overload protection circuits. With a heat sink, it can continuously provide 1A current. If peripheral devices are used, it can also provide impassable voltage and current. This article is mainly to talk about the role of lm7805 voltage regulator circuit capacitor.
As shown in the figure, in the LM7805 stabilized power supply circuit, each capacitor has its own role, among which:
C1 is a rectifier filter capacitor. It filters the rectified pulsating waveform into a DC voltage with a small ripple ripple. Its capacity is related to the load. Generally speaking, the heavier the load, the greater the value of C1 is required. The specific calculation is from here slightly.
C2 is required by the LM7805 voltage regulator integrated circuit, especially when the LM7805 and the filter capacitor of the rectifier circuit (here, C1) are not tightly connected, it is even more essential. It is used to stabilize the working state of the LM7805 internal amplifier. Its value is specified by the manufacturer and must not be less than 0.33 microfarad. Its connection must be as close as possible to pin 1 and pin 2 of LM7805.
C3 is also required by the LM7805 voltage regulator integrated circuit. It is used to stabilize the working state of the LM7805 internal amplifier and improve the transient response of voltage adjustment. Its value is the value specified by the manufacturer and must not be less than 0.1 microfarad. Its connection must be as close as possible to pins 3 and 3 of LM7805.
C4 is the decoupling capacitor of the load circuit, which provides a local loop with a terminal distance to the load, and its value is related to the working mode of the load.
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